Tense drama series about the different challenges faced by the British Security Service as they work against the clock to safeguard the nation. The title is a popular colloquialism for spies, and the series follows the work of a group of MI5 officers based at the service's Thames House headquarters, in a highly secure suite of offices known as The Grid.
Peter Firth
Harry Pearce
Nicola Walker
Ruth Evershed
Max Brown
Dimitri Levendis
Lara Pulver
Erin Watts
William Hope
Jim Coaver
Alex Lanipekun
Ben Kaplan
